diff --git a/UnrealHyperTwist/Source/UnrealHyperTwist/Private/HyperTwistSimulation/HyperTwistPuzzleViewerComponent.cpp b/UnrealHyperTwist/Source/UnrealHyperTwist/Private/HyperTwistSimulation/HyperTwistPuzzleViewerComponent.cpp
index ec4a79e..7023942 100644
--- a/UnrealHyperTwist/Source/UnrealHyperTwist/Private/HyperTwistSimulation/HyperTwistPuzzleViewerComponent.cpp
+++ b/UnrealHyperTwist/Source/UnrealHyperTwist/Private/HyperTwistSimulation/HyperTwistPuzzleViewerComponent.cpp
@@ -186,6 +186,18 @@ namespace HyperTwistPuzzleViewerComponentInternal
 				continue;
 			}
 
+			const FHyperTwistPuzzleDefinitionRef& PacketDefinition = ReplayPacket.PuzzleDefinition;
+			const FHyperTwistPuzzleDefinitionRef& SnapshotDefinition = Snapshot.State.Definition;
+			const bool bDefinitionMatchesPacket =
+				PacketDefinition.PuzzleId == SnapshotDefinition.PuzzleId
+				&& PacketDefinition.PuzzleFamily == SnapshotDefinition.PuzzleFamily
+				&& PacketDefinition.Dimension == SnapshotDefinition.Dimension
+				&& PacketDefinition.NotationProfile == SnapshotDefinition.NotationProfile;
+			if (!bDefinitionMatchesPacket)
+			{
+				continue;
+			}
+
 			OutContext.SceneContextId = !ReplayPacket.ReplayId.IsEmpty()
 				? FString::Printf(TEXT("replay/%s"), *ReplayPacket.ReplayId)
 				: Snapshot.SnapshotId;
@@ -662,8 +674,7 @@ bool UHyperTwistPuzzleViewerComponent::LoadReplayPacket(const FHyperTwistReplayP
 	{
 		SceneContext = ReplaySceneContext;
 	}
-	else if (!SceneContext.IsStructurallyValid()
-		|| SceneContext.PuzzleState.Definition.PuzzleId != ReplayPacket.PuzzleDefinition.PuzzleId)
+	else
 	{
 		SceneContext = FHyperTwistSimulationSceneContext();
 	}
diff --git a/UnrealHyperTwist/Source/UnrealHyperTwist/Tests/HyperTwistTwistyBound1ReplayShellTest.cpp b/UnrealHyperTwist/Source/UnrealHyperTwist/Tests/HyperTwistTwistyBound1ReplayShellTest.cpp
index 5998d0d..2fcb38c 100644
--- a/UnrealHyperTwist/Source/UnrealHyperTwist/Tests/HyperTwistTwistyBound1ReplayShellTest.cpp
+++ b/UnrealHyperTwist/Source/UnrealHyperTwist/Tests/HyperTwistTwistyBound1ReplayShellTest.cpp
@@ -208,4 +208,81 @@ bool FHyperTwistTwistyBound1ReplayShellTest::RunTest(const FString& Parameters)
 	return true;
 }
 
+IMPLEMENT_SIMPLE_AUTOMATION_TEST(
+	FHyperTwistTwistyBound1ReplaySceneContextMismatchGuardTest,
+	"HyperTwist.CleanRoom.TwistyJs.Bound1.ReplaySceneContextMismatchGuard",
+	EAutomationTestFlags::EditorContext | EAutomationTestFlags::EngineFilter
+)
+
+bool FHyperTwistTwistyBound1ReplaySceneContextMismatchGuardTest::RunTest(const FString& Parameters)
+{
+	static_cast<void>(Parameters);
+
+	UHyperTwistPuzzleViewerComponent* Viewer = NewObject<UHyperTwistPuzzleViewerComponent>();
+	TestNotNull(TEXT("Viewer component instance must be created."), Viewer);
+	if (Viewer == nullptr)
+	{
+		return false;
+	}
+
+	FHyperTwistReplayPacket ReplayPacket;
+	ReplayPacket.ReplayId = TEXT("replay-bound1-mismatch");
+	ReplayPacket.SessionId = TEXT("session-bound1-mismatch");
+	ReplayPacket.PuzzleDefinition = UHyperTwistContractLibrary::MakeSampleHyperPuzzleDefinition();
+	ReplayPacket.CaptureMode = EHyperTwistCaptureMode::Imported;
+
+	FHyperTwistStateSnapshot Snapshot;
+	Snapshot.SnapshotId = TEXT("snapshot-mismatch");
+	Snapshot.State = UHyperTwistContractLibrary::MakeSampleHyperPuzzleState();
+	Snapshot.DerivedHash = TEXT("snapshot-mismatch-hash");
+
+	ReplayPacket.Events = {
+		HyperTwistTwistyBound1ReplayShellTestInternal::MakeReplayEvent(
+			TEXT("evt-001"),
+			1,
+			0,
+			EHyperTwistReplayEventType::StateSnapshot,
+			HyperTwistTwistyBound1ReplayShellTestInternal::SerializeStructToJson(Snapshot)
+		),
+		HyperTwistTwistyBound1ReplayShellTestInternal::MakeReplayEvent(
+			TEXT("evt-002"),
+			2,
+			100,
+			EHyperTwistReplayEventType::Move,
+			TEXT("{\"notation\":\"R\",\"transformationRef\":\"classic/r\",\"source\":\"unit-test\"}")
+		)
+	};
+
+	TestTrue(
+		TEXT("The initial valid replay packet should populate a scene context before the mismatch case."),
+		Viewer->LoadReplayPacket(ReplayPacket)
+	);
+	TestTrue(
+		TEXT("The initial valid replay packet should mark the scene context as loaded."),
+		Viewer->GetPlaybackState().bSceneContextLoaded
+	);
+
+	Snapshot.State.Definition = UHyperTwistContractLibrary::MakeSampleClassicPuzzleDefinition();
+	ReplayPacket.Events[0].PayloadJson =
+		HyperTwistTwistyBound1ReplayShellTestInternal::SerializeStructToJson(Snapshot);
+
+	TestTrue(
+		TEXT("Replay packet load should still succeed when the packet remains structurally valid."),
+		Viewer->LoadReplayPacket(ReplayPacket)
+	);
+
+	const FHyperTwistViewerPlaybackState PlaybackState = Viewer->GetPlaybackState();
+	TestTrue(TEXT("Mismatch replay packets should still report the replay as loaded."), PlaybackState.bReplayLoaded);
+	TestFalse(
+		TEXT("Mismatch replay snapshots must not materialize a misleading scene context."),
+		PlaybackState.bSceneContextLoaded
+	);
+	TestFalse(
+		TEXT("Mismatch replay snapshots must clear any viewer scene-context state."),
+		Viewer->GetSceneContext().IsStructurallyValid()
+	);
+
+	return true;
+}
+
 #endif // WITH_AUTOMATION_TESTS